Industrial controllers are special-purpose computers utilized for controlling industrial processes, manufacturing equipment, and other factory automation, such as data collection or networked systems. At the core of the industrial control system, is a logic processor such as a Programmable Logic Controller (PLC) or PC-based controller. Programmable Logic Controllers for instance, are programmed by systems designers to operate manufacturing processes via user-designed logic programs or user programs. The user programs are stored in memory and generally executed by the PLC in a sequential manner although instruction jumping, looping and interrupt routines, for example, are also common. Associated with the user program are a plurality of memory elements or variables that provide dynamics to PLC operations and programs. Differences in PLCs are typically dependent on the number of Input/Output (I/O) they can process, amount of memory, number and type of instructions, and speed of the PLC central processing unit (CPU).
In a more macro sense than the controller, businesses have become more complex in that higher order business systems or computers often need to exchange data with such controllers. For instance, an industrial automation enterprise may include several plants in different locations. Modern drivers such as efficiency and productivity improvement, and cost-reduction, are requiring manufacturers to collect, analyze, and optimize data and metrics from global manufacturing sites. For example, a food company can have several plants located across the globe for producing a certain brand of food. These factories in the past were standalone, with minimum data collection and comparison of metrics with other similar factories. In the networked world of today, manufacturers are demanding real-time data from their factories to drive optimization and productivity. Unfortunately, conventional control systems architectures are not equipped to allow a seamless exchange of data between these various components of the enterprise.
Another requirement of modern control system architectures is the ability to record and store data in order to maintain compliance with Food and Drug Administration regulations such as Regulation 21 CFR Part 11. One common solution for recording data includes providing a local recording module that often occupies a slot in a controller backplane such as a PC-Historian which is an industrial computer for the controller backplane, and employs a transitional layer to supply an indirect interface to the controller. This includes a platform that provides high speed, time series, data storage and retrieval with both local and remote control processors. The PC-Historian communicates with controllers directly through the backplane and can communicate remotely via a network interface. The PC-Historian allows archiving data from the controller to an Archive Engine which provides additional storage capabilities.
In general, industrial controllers are constructed in modular fashion to accommodate different applications requiring various numbers and types of input/output (I/O) circuits, as is determined by the particular device or process being controlled. The stored control program runs in real-time to provide outputs to the controlled process (e.g., electrical signals to outputs such as actuators and the like.) Accordingly, such controllers typically only deal with current value of data—as opposed to leveraging from data trends that are available to I/O modules associated with industrial units. Moreover, such controllers can become overloaded when a plurality of users simultaneously request data.